Struct mz_repr::relation::VersionedRelationDesc

pub struct VersionedRelationDesc {
    inner: RelationDesc,
}

A wrapper around RelationDesc that provides an interface for adding columns and generating new versions.

TODO(parkmycar): Using an immutable data structure for RelationDesc would be great.

Fields

inner: RelationDesc

Implementations

impl VersionedRelationDesc

pub fn new(inner: RelationDesc) -> Self

pub fn add_column<N, T>(&mut self, name: N, typ: T) -> RelationVersion

where N: Into<ColumnName>, T: Into<ColumnType>,

Adds a new column to this RelationDesc, creating a new version of the RelationDesc.

Panics

• Panics if a column with name already exists that hasn’t been dropped.

Note: For building a RelationDesc see RelationDescBuilder::with_column.

pub fn drop_column<N>(&mut self, name: N) -> RelationVersion

where N: Into<ColumnName>,

Drops the column name from this RelationDesc. If there are multiple columns with name drops the left-most one that hasn’t already been dropped.

TODO(parkmycar): Add handling for dropping a column that is currently used as a key.

Panics

Panics if a column with name does not exist or the dropped column was used as a key.

pub fn latest(&self) -> RelationDesc

Returns the RelationDesc at the latest version.

pub fn at_version(&self, version: RelationVersionSelector) -> RelationDesc

Returns this RelationDesc at the specified version.

pub fn latest_version(&self) -> RelationVersion

fn validate(&self)

Validates internal contraints of the RelationDesc are correct.

Panics

Panics if a constraint is not satisfied.

Trait Implementations

impl Clone for VersionedRelationDesc

fn clone(&self) -> VersionedRelationDesc

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for VersionedRelationDesc

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Serialize for VersionedRelationDesc

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.